Chain conveyer for heat-treating furnaces



Feb. '13, 1940; H. H. HARRIS CHAIN CONVEYER FOR HEAT-TREATING FURNACES 1 Rd N w o r E h T a N o m @w w v T e N T e I H A a 2 i W M mm H D Y 5 in Filed Oct. 14, 1937 Feb. 13, 1940. H. H. HARRIS 1 2,189,983

CHAIN CONVEYER FOR HEAT-TREATING FURNACES Filed Oct. 14, 1937 2 Sheets-Sheet 2 INVENTOR Henry H. Harris Y Prensa 55.1940 7' V UNITED STATES 2,189,983 01mm CONVEYER Fon HEAT-TREATING FURNACES Henry H. Harris, Champaign, Ill. Application October 14, 1937, Serial No. 168,906 2 Claims. (Cl. 263-8);

My invention relates generally to heat treat- ,ing furnaces, and specifically to the provision of an apparatus for conveying articles to be heat treated through such furnaces. Ordinarily, articles to be heat treated are travelled through furnaces either, if of sufiiciently large size, by being placed directly on skid rails or tracks or roller rails and being pushed through the furnace, or else, in those instances where the articles are of rather small size and are loaded onto supports, or trays as they are commonly called, and pushed through the furnace in tandem either on skid rails or tracks or roller rails. Myinvention, although applicable for use with larger articles, will be described with relation to its use with trays of the hinged type such as described and claimed in my Patent No. 2,022,283, for the conveying of smaller articles through heat treating furnaces For travel through the furnace, the trays are usually pushed in tandem, that is, pressure applied to the rearmost of the trays is communicated from one to the other in front thereof down the line until the tray at the far end of the line is pushed out of the furnace. This method has several distinct disadvantages. For one thing, it places severe and ultimately destructive compressive stresses on the trays themselves since they bear directly against one another in communicating the travelling pressure from one to the other thereof. For another thing, the process is slow and uneconomical. In order to operate properly, the line of trays must be continuous, and to pass even a single tray load through the furnace, it is necessary that an entire line of trays be assembled and loaded in order to effectively travel the one tray through. In such instances there is an enormous waste of power.

The main object of my invention is the provision of a method and apparatus for moving work supports such as trays or the like through furnaces quickly and economically.

Broadly, my invention consists in utilizing a pair of endless, continuous drag conveyer chains mounted for travel within the furnace and along the longitudinal walls thereof, and providing these endless, continuous chains with means to drag along therewith trays 'on which are disposed articles to be heat trea Other, and further objects of my invention will m part be obvious and in part pointed out spe- :iflcally hereinbelow in connection with the folowing description thereof In the drawings annexed hereto and made 9. art hereof.

Figure 1 is a side eievational view, partly in section, of one form of chain constructed according to and embodying my invention;

Fig. 2 is a bottom plan view, also partly in section, of the chain illustrated in Fig. 1, along the broken line 2-2 of Fig. 1;

Fig. 3 is a section on the line 3-3 of Fig. 1;

Fig. 4 is a section on the line 4-4 of Fig. 1;

Fig. 5 is an exploded view of the component parts of the form of chain illustrated in Figs. 1 to 4;

Fig. 6 is a crosssectional view through a conventional form of heat treating furnace with one form ofmy invention applied thereto;

Fig. 7 is a longitudinal sectional view through the furnace shown in Fig. 6, illustrating one form of the endless, continuous chain drive connection in elevation;

Fig. .8 is a plan view of a sprocket wheel showing a portion of the chain passing thereover;

Fig. 9 is a View similar to Fig. 2 of a modified form of chain constructed according to and embodying my invention;

Fig. 10 is a section on the line Ill-It of Fig. 9;

Fig. ll is a view similar to Fig. 1 illustrating the form of chain shown in Fig. 9 in operation; and

Fig. 12 is a view generally similar to Fig. 7', but illustrating in elevation a modification of my invention in which the endless, continuous chain drive of my invention is wholly contained within the furnace.

Referring specifically to Figs. 1 to 5, reference numeral l0 indicates one form of chain constructed according to and embodying my invention, which is formed ofa plurality of what I prefer to designate as I-mernbers it, connected and pivotally secured together by a plurality of what I prefer to designate as O-members it. Each I-member l2 comprises a one-piece metal casting of heat and corrosion resisting alloy, preferably of nickel, chromium and iron. Each member I! is provided with a straight body portion l6 and a pair of cross heads l8, l8 at the opposite ends thereof and at right angles thereto, so that member l2 as a unit generally resembles a capital letter I. Cross-heads l8, l8 are circular in cross-section and of substantially uniform thickness, and body portion I6 is preferably of like formation. I-members I! are pivotally secured together, as shown, by O-membersll, each of which comprises a pair of opposed elliptical rings 20, 20, having generally the form of a capital letter 0. These rings 20, 20 are also adjustment, at least one pair of O-members or thereof projecting inwardly from each side as indicated in Fig. 5, and welding together the meeting ends of extensions 22, 22, as indicated.

at 23, Fig. 3.

sembling of the parts comprising the chain. The

rings 20 are formed sufficiently wide and long enough to receive cross-heads I8, I8 loosely therewithin and to enable the I-members I2 to swing and pivot freely with respect to one another. This free pivoting movement is essential for proper operation of the chain as a whole, and while limited on one side because of the welded connection '23 between extensions 22,- 22, the pivotal movement between I-members I2 on the other side is practically unlimited.

Since the last pair I00 of O-members 20, 20 to connect the ends of a sprocket chain are ordinarily secured together by the user having no ,welding facilities and also to facilitate length rings IOI, IOI are connected up by means of upper and lower screws I02, as indicated in Figs. 1, 2 and 4. Chain-I0 can readily be opened, if necessary for repairs or other purposes by removing the screws I02 referred to above.

40 my invention may beemployed, which furnace sets of twin teeth BI, 52 on the wheels are so Referring to Figures 6, 7 and 8, reference numeral 30 indicates one form of furnace wherein comprises floor 32', side swalls 34, 34, front and back walls 36 and 38, having openings through which the chain-is passed, and roof 40. Chain I0 is carried by a number of sprocket wheels, disposed about driving wheel 42 and driven wheel 44. ,While in the form shown idler wheels 48 and 48 are provided, and also take-up wheel 50, to tighten the chain and take-up any slack therein which may develop through use, both the idler wheels-and the take-up wheel may be dispensed with if desired by providing compensating adiust-' ments between the drive wheel and the driven wheel, and in such case the return may be outside, instead of inside the furnace as shown. As shown in 'Fig. 7, all'of these wheels are disposed outside of furnace 30, with chain I0 passing within the furnace confines during both travel and return. If desired, the sprocket wheels may be disposed within the furnace also.

Drive sprocket wheel 42, driven wheel 44, takeup wheel 50, and, idler wheels 46 and 40, are all generally similar in construction, if not in size, having laterally spaced sprocket teeth 5|, 52 to define a peripheral groove 53 therebetween. The

spaced apart that when chain I0 passes therearound, body portions I8 of I-members I2,-will be received within the peripheral grooves 53, and O-members I4 will be received within the intersprocket spaces 54.

A. plurality of lugs or dogs are provided on chain I0, spaced apart; 'at predetermined distances, to engage trays to be travelled through the furnace and move same along through the Rings 20, 20 are duplicates of each other, though turned into reverse positions in the asiron,

lugs or dogs'comprise short bars welded to o-members I4 011 the back thereof and directly over the welded-together extensions 22, 22.

In the furnace as shown in Figs. 6 and "I, I provide a pair of H-beams 62, 62 disposed on furnace floor 32, extending longitudinally of the furnace and along the side walls thereof. During operative travel through furnace 30, in the direction of the arrow in Fig. '7, chain I0 passes through and along the upper channel 84 of beam 82, the side walls I50, 66 of which are short enough to permit lugs or dogs 60 to project upwardly therebeyond and engage the sides or ends of trays, as 68, to move same along therewith through the furnace. Leaving the furnace, tray 68 is de-' posited on a take-off platform (not shown) and chain I0 passed over driven wheel 44. Lugs 80 are still directed outwardly, but when passing over idler rollers 46, 48 the lugs are directed inwardly and provision is made, in the form of a deep peripheral channel I0 within wheels 48 and 48, to receive lugs 60. During return travel, chain I0 passes through furnace 30 in a reverse direction, within lower channel I2 of beam 62, and a slotted split rail 14 is provided to rest on furnace floor 32 and support the returning chain I0, its slot I5 receiving the-lugs or dogs 60.

As shown-in Fig. 6, the H-beams 62 serve as tracks for the tray 68, said tray 88 being supported near its outer edges on the top of beam walls 66, 66. A roller rail .16 may be centrally disposed within the furnace'between the side rails or beams 62 extending ldngitudinally thereof, to make a rolling contact with the underside of tray 68 at the middle thereof to facilitate movement of the tray through the furnace, and the tray may be hinged,

as indicated at 11. i In Figs. 9 to 11, 1 have illustrated a modified form of chain 80. In this form, also made up of one-piece metal castings of heat and corrosion re--v sisting alloy, preferably of nickel, chromium and I-members 82 are generally similar to 1- members I2, and are provided with cross-heads 83 similar tocross-heads I8 but instead of being connected by connectors made up of a pair of identical, but oppositely disposed 'O-members, as 20, members 82. are connected by caps 84 and 88, both of which have elliptical recesses therewithin to receive the ends of a pair of adjacent crossheads 83, 83. Caps 84 are flattened on top, but caps 88 are rounded on their undersides. In this modification, caps 84 and 88 are similarly provided with extensions 88, which are welded together as at 89 to complete the link unit. Also, lugs or dogs 80 are provided on chain 80, similarly welded over extensions 88 and projecting outwardly therefrom.

In the main form of my invention, chain I0 is travelled through the furnace and over sprocket wheels in a vertical plane. Using the modified form of chain 80, I am enabled to travel the chain through the furnace in a horizontalplane. In instances where it is either impossible or impractical to use space underneath the furnace floor level,,this horizontal travel may be necessary. In Fig. 9, chain 80 is shown travelling through a furnace with the rounded undersides of caps 86 sliding along on tracks or guideways 82 formed on the side walls of the furnace, with dogs 90 extending outwardly a distance sufilcient to engage and move along therewith the trays 94 resting on suitable supports such as skid rails 86. The rounded cap 86 supports the chain and reduces the friction on the chain supporting track 92.

75 furnace. As shown in Figs. 1, 3 and '7, ,these- In either modification, it will be. seen that the chain link construction is very simple, each link (I-o member) comprising but two parts when completed. The elliptical ring or cap construction provides "a large bearing surface upon the twin-toothed sprockets, and the relative pivotal' obtained. The turning eflect so produced within each O-member orpivoting member, as when the chain passes around a sprocket wheel, is divided up so that it takes place partly between the forward cross-heads and the O-member, and partly between the rear cross bar and the same O-memher or ring. Thus, not only is the wear more fully distributed, but also the radius of turning can be greatly decreased, and the entire arrangement of chain and sprocket wheels made much more compact than wouldotherwise be possible.

One form in which these sprocket wheels are located within the furnace is illustrated in Fig. 12. In this modified form of the invention, '1 provide a pair of H-beams 63, disposed on furnace floor 32, extending longitudinally of the furnace 30 and along the side walls thereof, similarly to beams 62 in Figs; 6 and 7. During operative travel through furnace 30, chain l passes around wheel 42 and through the furnace in one direction along the upper trackway 65, around wheel 44.

and back through furnace 30 on the lower trackway Bl. The side walls of H-beam 83 are widened, as at 69, to. provide journals for the drive and driven sprocket wheels 42, '44, in close proximity to the trackways, and the lower track-.- way 61 is provided with an inclined apron II, upon which chain l0 rides upon entering and leaving the lower trackway.- Such arrangement makes it possible to keep the entire chain drive connection within' the furnace. The source of power to actuate the shafts on which the sprockets are mounted may, if desired, come fromoutside the furnace. and the chain it may be kept under tension by a take-up arrangement of sprocket wheels 42, 44 (not shown). By keeping the sprocketwheels inside the furnace and in close proximity to the trackways over which the chain travels, heat transfer and loss occasioned bythechainoutsidethefumaceis avoided, and the cost of operation reduced.

3 The rounded O-members' 20 of chain Ill travel smoothly over the H-beam rails 62. The chain has'no projections on the sides thereof, other than lugs 60 to get. caught during travel through the furnace. Using-the, H-beam chain guiding 5 arrangement does away .with the necessity for any special brick work or chambering underneath the furnace and thus greatly reduces the cost of furnace construction'and operation. Ad-

tion is to be limited in scope only by the claims appended hereto, in which, for convenience, 1 refer to trays and other material to be heat treated as articles.

I claim: 1. In combination, a tray and means to convey same through a heat treating furnace, which conveying means comprise a pair of aligned and I spaced apart trackway members disposed on opposite sides of and extending the length of the furnace, a central supportingmember also within the furnace and extending the length thereof substantially midway between the trackways, the tray comprising a plurality of sections hinged together each of which sections is supported by 85 one trackway and the central support, and movable means associated with the trackways for engaging the tray and moving same through th furnace. a i

2. Incombination, a tray and means .to convey same through a heat treating furnace, which conveying means comprise'a pair of aligned and spaced apart trackway members disposed on opposite sides of and extending the length of the furnace, a supporting member also within the .furnace and extending the length thereof substantially midway-between the trackway-s, the

inthe r a my amass-4mm. 

